Die structure



Dec. 26, 1944. WILDY ET AL 7 2,366,077

DIE STRUCTURE Filed Aug. 3, 1942 JNVENTORQ 29 ERIC LAWRENCE WILDY Eg ALEXANDER JOHN SANDS ATTORNE Y Patented Dec. 26, 1944 pm STRUCTURE Eric Lawrence Wildy and Alexander John Sands, Westminster, London, England Application August 3, 1942, Serial No. 453,444, In Great Britain August 5, 1941 7 'Claims.

It is an object of the invention to provide an improved form of die for carrying out the process,

, is passed through a die comprising a hollow substantially conical ciip member supported by a a plurality of substantially radial arms which bear with lateral freedom against supporting surfaces to limit movement of the die in the direction of travel of the wire, said wire leaving the die through an orifice in theapex of the cup member, whereby the action of the coating material within the cup member serves to centralise the orifice relative to the wire. Conveniently the bearing surfaces which are engaged by the radial arms are disposed in a plane which intersects the wire at a position in advance of the die orifice, whereby the coating material draws the die to aposition of stable equilibrium.

There is further provided according to the invention a die for regulating the thickness of viscous coatings applied to wires and the like, comprising an inverted cup having a substantially conical interior and an orifice at its apex, said cup being formed with laterally extending arms arranged to-support the die against bearing surfaces so that it is free to centralise itself with respect to the coated wire or the like,- when the latter issues through the apical orifice.

Preferably the conical cup member has a normally closed radial slit, which-when opened, enables the die to be inserted radially upon the wire. Thus one of the radial arms may comprise a pair of overlapping strips which are normally pressed resiliently together, but which when separated serve to open the slit in the cup member.

As a further aspect the invention provides a machine for continuously coating a wire or the like with a viscous medium, comprising in combination a container for medium through which the wire or the like is drawn in an upward direction, a die in the form of a substantially conical inverted cup having at its apex an orifice through which the wire or the like is drawn after-leaving the bulk' of the medium in the container, and supporting means carried by the container and adapted to be engaged by a plurality of arms extending outwards from the conical' cup. Preferably a pair of sligned arms extend outwards from the conical cup at diametrically opposite points and each is caused to engage a downwardly facing supporting surface as the die is borne upwards by the movement of the wire or the like and the tenacity of theapplied coating medium, the die being free to move in a horizontal plane so as to centre the orifice with respect to the wire or the like.

The invention is illustrated by way of example in the accompanying drawing, in which:

Figure l is a side elevation of the die shown partly in section;

Figure 2 is a plan corresponding to Figure 1; Figure 3 is a side sectional elevation of a coating machine utilising the improved dies; and

Figure 4 is a fragmentary front elevation showing the means used for retaining the dies. Each of the'dies, of which there are usually several in a single coatin machine, takes the form shown in Figures 1 and 2 and comprisesv a strip ll) of bronze or other metal which is bent back upon itself, as shown in Figure 2, so as to form a loop [1 which constitutes a resilient hinge adapted to ensure that the two halves of the strip l0 lie fiat upon one another and press firmly together. The free ends I2 and I3 opposite to the loop are conveniently splayed so that they lie apart and thus facilitate the opening of the die when it is desired to position the latter around the wire which is to be coated.

At a position midway between the loop II and the splayed ends l2 and 13 the two thicknesses of metal strip are spread apart, say in a press, to produce a diametrally divided substantially conical inverted cup l4, the apex l5 of which is .formed with an axial orifice 16 of predetermined diameter, the size being such as to produce the desired th ckness of coating on a wire of prescribed diameter. The apex I 5 preferably projects above the upper edge of the metal strip III,

while the lower margin IT in the form shown is disposed in a plane extending between the upper and lower edges of said strip II]. It will be seen that the strip I 0 produces in effect a pair and a pair of end walls, one of which is indicated at 22. The front wall 2| serves as a support for a pairof blocks 23 and 24 which are clamped in position by a'plate 25 adapted to be tightened by a pair of butterfly nuts, one of which is shown at 26. The surface 21 of the with respect to the corresponding wire.

block 24 carries a layer 28 of resilient material such as compressed cork, while the adjacent surface of the block 23 is formed with a series of vertical grooves, one of which is shown at 29. These are for the passage of the wires which are to be coated, and which are indicated at 38, 3|

and 32 in Figure ,4. Thus the grooves 29 arev passes through a number of orifices 35 to form a pool of medium, which is indicated at 36. The surface level of this pool can be regulated by means of a plate 31, which is fitted to a spindle 38 and is thus angularly adjustable, the surplus medium being allowed to flow between the walls 28 and 2| and return to a storage tank (not shown) The dies, three of which are shown in the drawing at 39, 48 and 4| respectively, arecarried by a bracket 42 which is substantially J-shaped in cross section and which has a horizontal flange 43 adapted to be clamped to the top. |9 of the casing'by means of a screw 44. The vertical limb 45 of the bracket is formed with three rectangular openings, one of which is shown at 46 in Figure 3, and at corresponding positions the short limb 41 has vertical parallel-sided notches, one

of which is indicated at 48. When the machine is in use each die has its limb |8a inserted through the corresponding slot 46, while the limb llJb is retained in position within the notch 48 by 'a rectangular frame member 49, the upper and lower rails of which are indicated at 58 and respectively. Thisframe member is hinged at 52 to the bracket 42 and is arranged to be held in its closed position by a'catch 53. Each of the notches 48 is continued downwards, as at 54, in the form of a slot through which the wire 38 can be passed, but the lower portion of the bracket 42 has. a relatively large hole 55, through which coating medium can pass upwards with the wire 38 and can simultaneously flow back into the pool 36. The opening in the casing in front of the dies 39, 48 and 4| i arranged to be closed by a readily removable cover 51, leaving a slot 58 through which the wires 38, 3| and 32 pass upwardly.

It will be seen that by 'moving the frame 49 forwards about its hinge 52 the dies 39, 48 and 4| can be placed in position around the wires 38, 3| and 32 by slightly separating the halves of the dies, the splaycd ends of said dies then being inserted into the apertures 46 in the bracket 42.

The frame 49 is then returned to its closed position so as to embrace the other limbs |8b of the dies. Thus the under surface of the rail 50 and the upper end surface 56 of each of the slots 46 serve as bearers for the arms of the die and enable the latter to slide freely in any direction change its direction. This change of direction of the medium results in radial forces normal to the wire, which forces cause the die to move in a horizontal plane until the radial forces reach a state of equilibrium when the die is centralised about the wire. ponent which causes the die to lift upon th column of medium and thus come into contact with the upper rail 58 of the frame and the upper end 56 of the slot 46. The sloping internal wall of the die efiiciently centralises the die, for the conical cup has considerable depth, say 1% inch, and is symmetrical in all directions about its vertical axis, i. e, about the axisof the wire. Moreover the frictional resistance to this centralising movement is relatively slight, as the die has only two points in contact with its supporting member, namely those parts of the arms |8a and |8b which bear against the upper rail 58 of the frame 49 and the upper end 56 of the slot 46 respectively. Also the robustness of the die enables it to be made relatively small and light so that it floats readily upon the ascending column of medium. If desired the level of the pool 36 of medium can be such that during working the two pointsat which the die is supported, namely at 58 and 56, are flooded with medium, since this keeps the parts lubricated and thus enables the die to move particularly freely; the medium, however, should not reach as high as the apex l5 of the die. Moreover inlthese circumstances a regular circulation of medium from the interior of the die back to the reservoir or storage tank is ensured, and this promotes efficient working by relieving the die of air bubbles and foreign matter, .as well as by making sure that the wire is being coated with medium in a substantially uniform condition.

It will be appreciated that the invention is not limited to the example which has been described and that various modifications may be made. For instance, the conical die may be provided with only one radial supporting arm or with more than two, while alternative forms of supporting device may be used. Moreover, in some cases the die may depart from a truly conical shape; forinstance its interior may be in the form of a pyramid having a base of hexagonal or other regular shape. Also the improved dies may be used in other forms of coating machine than that described.

What we claim is:

1. A die for regulating the thickness of viscous coatings applied to wires and the like, comprising an inverted c'up member having a substantially conical interior and an orifice at its apex, said cup havinga normally closed radial slit, which, when opened, enables the die to be inserted radially upon the wire, a plurality of arms radially extending from said cupto support the die against bearing surfaces, said arms being so spaced around the cup that the die is free to centralize itself with respect to the coated wire or the like when the latter issues through the apical orifice, one of said radial arms comprising a pair of overlapping strips which are normally pressed resiliently together, but which, when separated, serve horizontally so that said die can centre itself to open the radial slit in the cup member.

2. A die for regulating the thickness of viscous coatings applied to wires and the like, comprising an inver ed cup having a substantially conical interior and an orifice at its apex, said cup having a pair of arms radially extending in line from diametrically opposite parts of said cup to support the die against bearing surfaces so that the I i There is also a vertical com-- faces, both of the radial arms being split lon-' gitudinally, the parts at the outer extremity of one arm being joined to constitute a resilient i opened, enables the die to be inserted radially hinge while at the outer end of the other arm the parts are shaped so that they lie apart and facilitate theopening of the cup member, which cup member is split adjacent each of said pair of faces, said arms being so spaced around the cup that the die is free to centralize itself with respect to the coated wire or the like, when the latter issues through the apical orifice, each of said arms being of flat, rectangular cross section,

with that edge which faces the direction of travel of the wire disposed in advance of the apical 5. A die for regulating the thickness of viscous Y coatings applied to wires and the like, comprising an inverted cup having a substantially conical interior and an orifice at its apex, said cup having a normally closed radial slit which, when upon the wire and a pair of arms radially extending in line from diametrically opposite parts of said cup to support the die against bearing surfaces so that the die is free to centralize itself with respect tothe coated wire or the like when the latter issues through the apical orifice.

6. A die for regulating the thickness of viscous coating applied to wires and the like, comprising an inverted 'cup having a substantially conical interior andan orifice. at its apex, said cup having a pair of arms radially extending in line from diametrically opposite parts of said cup to support the die against bearing surfaces so that the die is free to centralize itself with respect to the coated wire or the like when the latter issues through the apical orifice, each of said arms being of flat, rectangular cross section, with that edge which faces the direction of travel of the wire disposed in advanceof the apical orifice.

7. A die for regulating the thickness of viscous coatings applied to wires and the like, compris ing an inverted cup having a substantially conical interior and an orifice at its apex, said cup having a pair of arms radially extending in line from diametrically opposite parts of said cup to support the die against bearing surfaces so that the die is freeto centralize itself with respect to the coated wire'or the like when the'latter issues through the apical orifice, each of said arms being of flat, rectangular cross section, with that edge which faces the direction of travel of the wire disposed in advance of the apical orifice, said cup having a radial slit which, when opened enables the die to be inserted radially upon the wire.

ERIC LAWRENCE W ILDY. ALEXANDER JOHN SANDS. 

